Exposure to mixtures of toxicants (e.g., pesticides) is common in real life and a subject of current concern. The present investigation was undertaken to assess some toxicological effects in male rats following exposure to methomyl (MET), abamectin (ABM), and their combination (MET+ABM), and to evaluate the ameliorative effect of zinc co-administration. Three groups of rats were designated for MET, ABM, and the mixture treatments. Three other groups were designated for zinc in conjunction with the pesticides. Additionally, one group received water only (control), and the other represented a positive zinc treatment. The obtained results revealed that MET was acutely more toxic than ABM. The tested pesticides induced significant elevation in lipid peroxidation and catalase levels, while declined the levels of the other tested parameters e.g., Superoxide dismutase (SOD), Glutathione-S-transferase (GST), Glutathione peroxidase (GPx), Glutathione reductase (GR), Cytochrome P450 (CYP450), testosterone, and thyroxine). Biochemical alterations induced by the mixture were greater than those recorded for each of the individual insecticides. The joint action analysis, based on the obtained biochemical data, revealed the dominance of antagonistic action among MET and ABM. Zinc supplementation achieved noticeable ameliorative effects. It was concluded that zinc may act as a powerful antioxidant, especially in individuals who are occupationally exposed daily to low doses of such pesticides.

The experimental design was a complete randomized blocks design with two treatments for imidacloprid and tetraconazole in addition to control. Each treatment includes three replicates. The application was carried out using knapsack sprayer equipped with one nozzle. Its residues on and in cucumber fruits collected after one hour, 1, 3, 5, 8, 11, 15 and 21 days from last spray were lower than the maximum residue limit (MRL) of imidacloprid and tetraconazole on cucumber fruits. The results obtained revealed that the residual level of imidacloprid was less than the maximum residual level (MRL=1 mg/kg) which recommended by Codex Alimentration Commission, and the residual level of tetraconazole was less than the maximum residual level (MRL=0.2 mg/kg) which recommended by Codex Alimentration Commission. Also, the results showed that tetraconazole high persistence (t 1/2 =1.4 days) than imidacloprid (t 1/2 =2.2 days) on cucumber fruits.

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The present study was carried out to determine the residues of the neonicotinoid insecticide imidacloprid , and the fungicide tetraconazole and their persistence in and on cucumber fruits after whitefly and powdery mildew control .The field experimental design was a complete randomized blocks design with two treatments for imidacloprid and tetraconazole in addition to control (42m 2).The application was carried out using knapsack sprayer equipped with one nozzle. Cucumber fruits samples were collected from each replicate (one Kg) at time intervals of one hour after application(zero time), 1 , 3 , 5 , 8 , 11 , 15 and 21 days after treatment with imidacloprid and tetraconazole. Estimation of imidacloprid residues were performed by High pressure liquid chromatography equipped with diode array UV detector .Quantitative analysis of tetraconazole residues were performed by Perkin gas chromatograph (GLC), equipped with electron capture detector (ECD. Result indicated that the recovery percentage of tetraconazole and imidacloprid were 91.62 % and 117.5% respectively. The initial deposit (one hour after application) was 0.943 mg/kg. while the detected residue amounts were 0.365, 0.271, 0.226, 0.086, 0.049, 0.028 and 0.013mg/kg of imidacloprid after 1, 3, 5, 8, 11, 15 and 21days of treatment, respectively. The calculated half life (t 1/2) value of this insecticide was 2.2 days. On the other hand the initial deposit of tetraconazole on and in cucumber fruits was 0.1742 mg/kg The obtained residual half-life value (t 1/2) of tetraconazole on and in cucumber fruits was 1.4 day. Data also revealed that the first day following application is critical in the sense of sharply decrease that reach 61.29% from the initial deposit of imidacloprid on cucumber fruits, but the loss of tetraconazole at first day was 40.41% from the initial residues on cucumber fruits.